Arming device



Sept. 19, 1950 c. N. HICKMANA ARMING, DEVICE Filed Aug. 22, 1946 Blarfenca N- Hickman.

Wz M-w Patented Sept. 19, 1950 signor to the United States. at as rep.- resented by the Secretary? of the Office: of Scion.

tific. Rcsearchand; Development in. the- Qfllce for Emergency Management Application August 22, 1946, Serial No; coarse w wz-cwa (Granted under the act of March I}, 1883,, as

amended April- 30, 1928-;"370 G; 757") 3 Claims.

The invention described herein may be manufeatured and used by or for the Government for governmental purposes, without the payment" to me of any royalty thereon.

My invention relates to a new and useful improvement in arming devices for fuzes and more especially designed for use in impact fuzes for explosive charges in rocket projectiles; Such fuzes must be made "projector safe" by some form of safety device disarming the fuze until on cage wires 6 carried by the head I. Adoughthe projectile has left its projector. Heretofore nut igniter P for the propellent assembly has an ithas been usual in such fuzes to arm them by electric squib 8 with wiring 9 introduced through the force of inertia due to the linear acceleration nozzle 4. of the projectile or by centrifugal force due to The head I has anaxial bore I 0, in the-rear the rotation of the projectile However; in the face [-41 of the rear wali l"-b,' which connects use of rocket projectiles, these forces are often forwardly wi h H" ibole H f l diameter, slight, and in many cases the projectile is nonforming the-shoulder [-0, and extended for rotative in flight. Consequently, arming devices wardlythrough the front face. l-d of the rear so actuated would be so sensitive that arming wali I-b. The fuze bcdy i lisreceived in these might 'be due to accidental dropping of the probores I 0 and H in the rear wall I"--b of the head jectlle. and extends forwardly of front walls I'--d into My invention is-designed to provide a fuze havthe head i. The body H has a reduced-cylin ing an arming device obviating such objectionable drical rear porti n -12, n enl r ed intermedi' features, since the device maintains the fuzeunate portion l'2--b-, and a reduced exteriorly armed irrespective of shock or im act ri r-ti threaded forward. portion. 1 z-c. When the fuze the launching of the rocket projectile. Th esbody 12 is seated in rear wall lb, the rear' en-d sential feature of my improved arming device is of the rear portion il a registerswithrear the provision of a thermally frangible bond for the rear Shoulder: w n li the firing means for cl'etonating the explosive Po and enlarged Dortifln a s charge of the projectile. bond maintains a s ll 1 a h wa d S oulder the firing means inoperative prior to launching, be ween enlarged l fl tion l 2-b and re and is dissolved icy the heateffect of the combusduced portionli'---c registers withv front face tion of the propellent charge of the projectile on Id of rear wall: l"-h. The body 12* has an-axifal launching. The fuze is armed only after the bore Il -i extending rearwardly' from the front projectile has been launched, and functions to end of body l2, through portions I2'-c and-12% detonate the explosive charge-by impactof the nd in o p rtion 12 -00, 1 tr nsverse wall Ii -g] projectile on'the target. having an axial-bore l t-hcommunicating with While 1 have illustrated in the drawing filed an a bore I514" extending rw rdly from herewith and have hereinafter fully described t e wa l 2- -01) the r end rb r 12. he one specific embodiment of my invention, it is to 40 axial il -f 'fi at its forwardi be distinctly understood that I do not consider and has t rea ed e e n fio 'i 1-310 e my invention limited to said specific embodiment, primer 1? for the booster charge 0: con ainer but refer for its scope to the claims appended M threaded" h forward p r 'e 1 h t of body l2, and having a-sleeve H-w threaded In the drawing: into the bore l-Z-f ahead of container l3. The Fig. 1 is a longitudinal section partly in. elevam r charge Cf uitably disposed in the: tion, of a rocket projectile provided with my im- DI Q' h ge E. in the head y e container proved arming device for an impact fuze. f4 projecting forwar y O W l {l -bi into file.

Fig. 2 is a fragmentary enlarged section of the Charge The container 13' has an axial fuze and arming device. 13 a (Fig. 6), and ,a peripheral flange 13-h. on

Fig. 3 is a section of. a socket member for a its rear fa e f ;ah0ut r ar nd of bore '3i'o, mass of fusible materialefiecting the thermally The firing, pin assembly" [his .slidably mounted, frangible bond. in bore 12-4, and comprises a body l5-a; (Figl Fig. 4 is a side elevation of the firing means 4) from the forward end of which projects the assembly. firing pin I5-b and from the rear end of which ig. 5 is-a side elevation, partly insection of the fuze body. 3 Fig dis a section of a containerfora primer.

illustrated in the drawing, the. rocket ic'- jectil'e has a charge-carrying head. i with a removable nose 2, and a motor casing 3 threaded to the head I, and'having the rear nozzle Suitably mountedin the casing 3 is the propellent assembly comprising the powder: grains 5 has a peripheral groove [-2 for receiving there-i 1;

in a safety pin (not shown) passed through the rear wall I-b and body l2, to secure the fuze against accidental discharge prior toflfiring the projectile. The socket for the fusible element comprises a tubular sleeve orthimble I I exteriorly threaded and received into' -the-"thre'aded bore lZ-z' of the fuze body [2. The rod l5-c of the firing pin assembly 15, extending rearwardly projectile has been fully launched. In such fuzes premature discharge of the explosive charge is prevented even if the detonating charge should be acci'dentallygischarged. ,By, the ,use of my improved thermally frangible bo'nd a slide may be held against spring action to maintain the lead in train interrupted. In firing, the bond is from body l5-a, passes loosely through bore l2h of body 12 and extends rearwardly into the sleeve [7. A mass l8. of any. suitable form of fusible material, such as low melting solder, is introduced into sleeve I! so as to surround the rear end of rod |5 c. Ihe outer surface of the rear end portion of rod I5--c, and the inner surface l'l-a of sleeve ,1] may be threaded,

knurled or otherwise roughened tdfortify' the bonding of the parts by the mass 18., Thesleeve 1 extends rearwardly from the fuze body [2 into the bore 'l-a of the igniter 1, and its rear end is closed by a rear wall ll--b provided with transverse slot |1--c for. a tool for'seating the sleeve I! in bore l2-i.

When the body l2 containing only the firing pin assembly [5 has been seated inrear wall l-b of head I (nose 2 being removed) bypassing the body I2 through the front. end of wall l-b, the sleeve l1 containing-the mass I8 is passed partially over the rear portion of rod l5-c. Heat is then applied to sleeve I1 sufficient to fuse the mass I8 and the sleeve is thenset up in bore IZ-i (as illustrated in Figs. 1 and 2). On cooling, the mass l8 bonds the rod 'l5- c to sleeve 11, thereby preventing movement of firing pin assembly l5 until mass I 8, is fused by-application of a sufficient degree, of heat,v When these parts have :been thus assembled, with the safety pin seated in groove l5 e, the spring I6 is inserted and container I3 is screwed into its place against forward end of spring H5 in bore l2f. The primer P is placed in container 13 andcontainer I4 is placed with its booster charge C. The propellent assembly is then mounted onthe rear head I by attaching wires 6, and igniter I with squib 8 and wiresil'ispositioned about the rear end of sleeve H, The casing 3 is then passed about wires 9 and grains 5 and attached to. head I, The head I is then charged with the explosive charge E through its openforward end, and the nose 2 is positioned to closehead l.,., 1

-. When the projectile is to be launched, the safety pin is withdrawn from groove I5 -e and the propellent assembly is fired in the conventional manner by an electrical charge conveyed by wires 9 to squib 8 firing the igniterl and grains 5. The heat generated by the combustion of the propellent assembly fuses the mass l8, releasing rod- |5-c from sleevell, and arming the fuze which functions on impactlof the projectile on the target, causing the firingpin- |5.-b to move forwardly against pressure [offspring Hi to fire primer P by percussion, exploding booster charge C and explosive charge.E.",' f.

" It is obvious that'myfdevic"' may be utilized to arm a detonator safe"fuze, viz. a fuze in which the lead in train isuinterrupted until the destroyed and the spring moves the slide to position the lead in train uninterrupted, to arm the fuze; 7 "1:

.Having described my invention, what I claim is: 1. In an arming device for a projectile fuze, the combination of a body; a firing pin slidable 'ins'aid body and having a shank; a sleeve mounted on said body andsurrounding a portion of said shank; a mass of fusible material in said sleeve bondingsaid shank to said sleeve; and a combustible charge adjacent said sleeve, said charge being fired on launching of the projectile and said mass being fused by the heat of combustion of said, charge to'release. said shank from said sleeve toarm the fuze.

2. an arming device for a projectile fuze, the combination of abody, a percussion primer in saidbody; a firing pin for; firing said primer, slidable in said body; 1 a spring spacing said v pin from said primer, said spring being so compressed by said pin that the pin'fires the'primer on im, pact of .the projectile on the target; a sleeve adjustably mounted on said body a rodslidable in said body and said sleeve a nd -having said pin mounted thereon; a fusible-massin said sleeve immobilizing said rod said pinby -a,ther mally frangible bond of said rod to said sleeve; and combustible means adjacent said sleeveto fuse said mass by the heat ofcombustion of said means to dissolve saidbond, said means being fired on the launching of the projectile.

3. In a projectile-havinga forward explosive; containing section and a rearward motor cham: ber section, a transverse wall separating saidsece tions, a fuze body fixed said walland having a longitudinally-extending passageway, a primer closing theforward end of-said passageway,,a firing pin slidable in saidpassageway in response to impact to engage and initiate s'aid -primer,. a thimble having its open end secured in saidfuze body and its'closed rearward end exposed to the motor chamber, a rod secured atone end-to said firing pin and having its other end extending into the rearward end of said thimble, .and amassoflow melting point alloyin s'aid thimble andcon necting the exposed end of the same withthe 'ad jacent end of the rod whereby the firing pinis positively held out of engagement withthe primer until the alloy is melted by heat generated in the motor chamber. I ,J,

CLARENCE REFERENCES CITED The following references are of record in the file of this patentl r I 1 UNITED STATES --PATENTS Number Name V Date,

340,935 Butler "Apr. 27, 1886 2,145,507 Denoix .Jan.' 31, 1939 2,400,128 Moore 'May 14, 1946 FOREIGN PATENTS:

Number Country h Date 2,769 Great Britain Of 1890 241,941 Great Britain' Nov. 26,1925 

